Skip to main content
Menu
Home » What's New » Understanding the Eye Chart

Understanding the Eye Chart

eyechart

Eye charts of different variations have become a standard in vision screenings and eye exams. One of the most familiar charts associated with vision is the Snellen eye chart, designed by Dutch ophthalmologist Hermann Snellen in 1862 to measure visual acuity- how well you can see at various distances.

Although there are variations of the Snellen chart used today, a traditional Snellen chart has eleven lines of block letters. The first line has one very large letter, which is one of several letters, for example E, H, or N. The following rows have increasing numbers of letters that become smaller in size as you read from the top to the bottom of the chart. The letters used on the chart are C, D, E, F, L, N, O, P, T, and Z.

When taking a vision exam, one eye is covered and you are asked to read the letters of each row aloud beginning at the top of the chart. The smallest row that you can read correctly indicates the visual acuity in the eye being tested.

The chart is positioned at a distance of 20 feet in the United States or 6 meters in the rest of the world. The term 20/20 vision is used to indicate the clarity and sharpness of your vision measured at a distance of 20 feet. If you have 20/20 vision, you can see clearly at 20 feet objects that can normally be seen at that distance. If you have 20/40 vision, it means that you need to be as close as 20 feet to see what a person with normal vision can see at 40 feet. The largest letter on an eye chart often represents an acuity of 20/200 which is associated with the term "legally blind."

You will be asked to read the letters one eye at a time. Some people can see well at a distance, but are unable to bring nearer objects into focus, while others can see items that are close, but cannot see them far away. By having you read the chart, your eye doctor is able to ascertain whether you have difficulty with distance vision and can determine which corrective lenses can be used to improve it. Near vision problems or other vision and eye health issues may not be detected with the Snellen eye chart alone, so a comprehensive eye exam is always recommended.

The next time you hop into the chair at your optometrists' office, you'll be able to understand why you have to read the letters on the chart in front of you and what the results mean for your vision.

Call Our Two Locations!

Holiday BOGO Email Header

Buy one frame and lens and get the second pair Free!

November 11 - December 31

Don't let your Flex Spending or Health Spending accounts expire!

*Cannot be combined with insurance. Free pair is of lesser or equal value to first pair.

Dear Patients,

As of Tuesday evening, March 17th, the CDC has recommended that all routine eye care be deferred until further notice, in order to slow the transmission of COVID-19 through our community.

Please be assured that we are still available to triage all urgent and emergent calls during this challenging time.

We are officially closing our offices effective at 3:00pm today, March 20 th and tentatively plan to reopen on April 1 st . We are rescheduling all routine visits and are available by phone to triage ocular emergencies.

Our phone lines will be open:

Monday the 23 rd and 30 th : 10:00am to 5:00pm

Tuesday-Friday (24 th -27 th and the 31 st ): 9:00am to 3:00pm

What does this mean?

1) If you are scheduled for an annual eye examination we will tentatively reschedule you starting April 1 st

2) If you are running out of a medication please contact us and we can transmit a refill electronically to your pharmacy.

3) If you have an issue which cannot wait for an office visit, contact us and we will schedule a Telephone appointment with one of our doctors. Medicare has temporarily relaxed its telehealth rules to allow this type of communication during the pandemic crisis. Other insurers may follow suit and allow for reimbursement of virtual care costs. The consultation must be initiated at your request.

4) If you have an ocular emergency we are, as always, available to help you at any time. Call 1-850-455-0120 andwait for instructions at the end of the message.

Dr. Leonard or Dr. Charbonneau will discuss your condition by phone and make the best treatment decision for you on a one on one basis.

5) Please remember that 80% of COVID-19 cases are mild and resolve within a week. However, if you feel your symptoms are worsening, call ahead before visiting your doctor’s office or emergency department and tell them you have or may have COVID-19. This will help the office protect themselves and other patients.

The CDC has many wonderful resources. Arming yourself and your family with clear information will help you avoid undue stress.

https://bit.ly/2WxWYIe and https://bit.ly/33FBlXZ

Together we will weather this storm.

With sincerest wishes for your continued good health we remain at your service,

Dr. Clare L Leonard

Dr. Mary Charbonneau